The Spewing Pumpkin


To create carbon dioxide and learn about chemical reactions


  • Pumpkin-carved into a jack-o-lantern*
  • Baking soda
  • Vinegar
  • Food coloring (optional)
  • Dishwashing liquid
  • Measuring cups
  • Wooden craft stick (or something for stirring)
  • Foil pan (or something to catch the reaction/spill)

*If you don’t want to buy/carve a pumpkin, any small container where the reaction can spew over the top or through the orifices will work.

*You may need to adjust the ingredient amounts (these do not have to be exact) depending on the side of your pumpkin/container and the size of the reaction you desire.


Place your carved pumpkin or container in the center of the foil pan/cookie sheet, etc. This will aid in later clean-up! Pour the baking soda (about a half cup) into your pumpkin or container. Next add some food coloring to a cup of vinegar as well as a few squirts of detergent. (The food coloring and detergent are for esthetics only.) Stir. Then pour the liquid mixture into your pumpkin. Watch out!


Foam springs up and over the container (or through the pumpkin’s eyes, nose, and mouth).The baking soda reacts with the vinegar to produce carbon dioxide gas. This is an example of a chemical reaction.